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Database Articles
Page 514 of 547
Count how many rows have the same value in MySQL?
To count how many rows have the same value using the function COUNT(*) and GROUP BY. The syntax is as follows −SELECT yourColumName1, count(*) as anyVariableName from yourTableName GROUP BY yourColumName1;To understand the above syntax, let us first create a table. The query to create a table is as follows −mysql> create table RowWithSameValue −> ( −> StudentId int, −> StudentName varchar(100), −> StudentMarks int −> ); Query OK, 0 rows affected (0.55 sec)Insert some records with same value. Here, we have added same marks for more than one student for our example. The query ...
Read MoreSearch for a string within text column in MySQL?
You can search for a string within text column in MySQL with the help of LIKE clause. The syntax is as follows −select *from yourTableName where yourColumnName like '%anyStringValue%';To use the above syntax, let us first create a table −mysql> create table SearchTextDemo −> ( −> BookName TEXT −> ); Query OK, 0 rows affected (0.55 sec)Insert some strings in the table. The query is as follows −mysql> insert into SearchTextDemo values('Let us C'); Query OK, 1 row affected (0.28 sec) mysql> insert into SearchTextDemo values('C in Depth'); Query OK, 1 row affected (0.14 sec) ...
Read MoreSelect records from MySQL NOW() -1 Day?
To get records from NOW()-1 Day, you can use the following syntax −select *from yourTableName where yourColumnName >=now()-interval 1 day;To understand the above syntax, let us first create a table. The query to create a table.mysql> create table GetRecordsFromNow −> ( −> YourDateTime datetime −> ); Query OK, 0 rows affected (1.76 sec)Now insert some dates into the fields. The query to insert records are as follows −mysql> insert into GetRecordsFromNow values(date_add(now(), interval 3 day)); Query OK, 1 row affected (0.28 sec) mysql> insert into GetRecordsFromNow values(date_add(now(), interval -1 day)); ...
Read MoreHow to change the column position of MySQL table without losing column data?
You can change the column position of MySQL table without losing data with the help of ALTER TABLE command. The syntax is as follows −ALTER TABLE yourTableName MODIFY yourColumnName1 data type AFTER yourColumnName2;To understand the above concept, let us create a table. The query to create a table with some columns is as follows −mysql> create table changeColumnPositionDemo −> ( −> StudentId int, −> StudentAddress varchar(200), −> StudentAge int, −> StudentName varchar(200) −> ); Query OK, 0 rows affected (0.72 sec)Let us insert some data in the table. The query to insert records is as follows -.mysql> insert into changeColumnPositionDemo ...
Read MoreDelimiters in MySQL?
Delimiters can be used when you need to define the stored procedures, function as well as to create triggers. The default delimiter is semicolon.You can change the delimiters to create procedures and so on. However, but if you are considering multiple statements, then you need to use different delimiters like $$ or //.Here we have a table “GetRecordFromNow” wherein the following are the records −+---------------------+ | YourDateTime | +---------------------+ | 2018-12-07 22:30:18 | | 2018-12-03 22:30:31 | | 2018-12-02 22:30:41 | | 2018-12-01 22:30:56 | | 2018-12-03 22:31:04 | +---------------------+ 5 rows in ...
Read MoreHow to get primary key of a table in MySQL?
To get the primary key of a table, you can use the show command. The syntax is as follows −SHOW INDEX FROM yourDatebaseName.yourTableName WHERE Key_name = 'PRIMARY';Suppose, we have a table with two primary keys; one of them is “Id” and second is “RollNum". The query for a table is as follows −mysql> create table TwoOrMorePrimary −> ( −> Id int, −> Name varchar(200), −> RollNum int −> , −> Primary key(Id, Age) −> ); Query OK, 0 rows affected (0.85 sec)Apply the above syntax to get primary key of a table. ...
Read MoreMySQL command line client for Windows?
In order to install MySQL command line client for Windows, you need to visit the following URL to get the download link https://dev.mysql.com/downloads/mysql/ −The snapshot is as follows −After that you need to select operating system. The snapshot is as follows −You need to choose Windows (x86, 32/64-bit) and download the installer.
Read MoreDo a select in MySQL based only on month and year?
To select MySQL based on month and year, use in-built function YEAR() and MONTH(). The syntax is as follows −select *from yourTableName where YEAR(yourColumnName) = YearValue AND MONTH(yourColumnName) = monthValue;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table selectDataOnYearandMonthDemo −> ( −> BookId int, −> BookName varchar(100), −> BookDueDate datetime −> ); Query OK, 0 rows affected (0.57 sec)Now you can insert some records in the table. The query is as ...
Read MoreCheck if a user exists in MySQL and drop it?
To check how many users are present in MySQL, use MySQL.user table. The syntax is as follows to check how many users are present.mysql> SELECT User FROM mysql.user;The following output displays the users −+------------------+ | User | +------------------+ | Mac | | Manish | | mysql.infoschema | | mysql.session | | mysql.sys | | root ...
Read MoreHow to front pad zip code with “0” in MySQL?
To front pad zip code with 0, use LPAD() function in MySQL. The syntax is as follows −SELECT LPAD(yourColumnName, columnWidth+1, '0') as anyVariableName from yourTableName;To understand the above concept of LPAD() to add front pad zip code with 0, let us create a table. One of the columns of the table is Zip Code. The following is the query to create a table.mysql> create table ZipCodePadWithZeroDemo −> ( −> Name varchar(200), −> YourZipCode int(6) −> ); Query OK, 0 rows affected (0.44 sec)Insert some records in the table. The query to insert records is as follows ...
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